The long term objective is to elucidate the relationship between the structure of mammalian salivary gland cells and diet and oral health and to better understand form-function complexes in exocrine glands. The specific aims to be pursued include the following. Salivary gland structural variation will be studied in an order of mammals having great ecological, particularly nutritional, diversity. Correlations will be sought between salivary gland histology and ultrastructure and several biological parameters, including diet and behavior. Salivary gland structural features that might have physiological significance will be described that will reveal the range of variation in the secretory process (beyond that known from studies of conventional laboratory animals) will be sought and described. A number of significant salivary gland features known at present only from preliminary data will be studied in detail. These include: 1) a totally new type of green salivary gland in pollen and nectar feeding bats; 2) a unique salivary gland having the form of thyroid-like follicles; 3) a new organelle in sexually dimorphic seromucous cells; 4) secretory granules with multiple limiting membranes that shed into the gland lumen; 5) the presence of a new membrane structure (portasomes) involved in sodium-transport in certain species that feed on fruit or insects; 6) unusual variations in the morphology of mitochondria; and 7) the occurrence of salivary gland virus infections in free-living (natural) populations of mammals. Lastly, salivary gland structural features will be compared to incidence of dental caries and periodontal disease in a variety of mammals known to have different incidences of disease in order to elucidate the possible relationships among these three items. Transmission electron microscopy will be the main methodology. Techniques have been developed that will allow collection and adequate preservation of salivary gland tissues under field conditions, which means that now a wide variety of mammalian species previously unavailable for research can be considered as potential models for health-related research in oral biology.